Issue link: https://read.dmtmag.com/i/307101
www.goodfruit.com GOOD FRUIT GROWER MAY 15, 2014 33 While the regions now share the same pest, its phenology is quite different. In Washington, for example, the pest seems to be knocked back (though not elimi- nated) by cold winter weather. Popu- lations build up in orchards over the summer and peak in the fall. The insect does not go through a winter diapause. In California, where the temperature rarely drops below freezing, the insects are active year round in at least one host crop, said Haviland. In cherries, popula- tions tend to peak in the spring and fall and decline in the winter and during the extreme heat of the summer, after the cherries have been picked. "Here, we don't catch anything in the summer because it's hot and dry. It can get to a hundred degrees every day for a couple of months," he said. "It's very, very different. Our big catches here are October through February." New lure A new lure for spotted wing drosoph- ila, which is based on research from U.S. Department of Agriculture researchers and commercialized by Trécé, Inc., is a valuable tool that should improve a grow- er's ability to monitor the pest, Haviland said. He tested the lure for a year and a half before it came on the market in April. The lure consists of two small plastic-coated containers that can be attached together to the top of a bucket trap using a paper- clip. The drowning solution in the trap can be just water or water with antifreeze, which helps preserve the insects and stops them from turning slimy before they are counted. In his evaluations, the lure was as effective in attracting spotted wing dro- sophila as apple cider vinegar, which is commonly used as an attractant. If apple cider vinegar is used as the drown- ing solution with the new lure, it catches three times as many flies as when the bait is vinegar alone. Whereas in Washington growers mon- itor for the arrival of the pest during the growing season, California growers can assume it's already there. They make two or three applications of pesticides within three weeks of harvest, starting when the cherries change color. The main purpose of monitoring for spotted wing drosoph- ila is to find out how effective a spray has been and if fly populations are build- ing up to the point where another spray is needed. By monitoring populations they might be able to extend the interval before they need to reapply. Haviland said growers might want to use the combination of the lure and vinegar if they're trying to catch the maximum number of flies. How- ever, besides increasing the number of spotted wing drosophila caught, the vinegar attracts a lot of other insects and different species of drosophila, which makes servicing the trap more difficult. If the grower doesn't care so much about the number of flies and wants to make the trap easier to read, then the new lure works well, he said, not- ing that researchers at this point can't tell growers what the number of flies means in regard to treatments. "There's no treatment threshold," he said. • 1615 W. Ahtanum • Yakima, WA 98903 • 509-248-8785 EXT 612 www.orchard-rite.com Get the Orchard-Rite® story from your nearest representative: W e have grown about 20 acres of cherries for 25 years or so. Usually, in a cold year, we won't have a crop in about half of the orchard. We've always had a problem with production on the east side of the orchard. In 2007, we actually froze out, which happens about every fourth year. This year, with our Orchard-Rite ® Wind Machine, we had an even crop throughout. The wind machine made all of the difference. The Auto Start option has also been a great advantage since we live 20 miles from the farm. I may put in another machine, but with the amount of air movement I'm getting, I think I'm covering the whole acreage. Larry and Pat Wildman Salem, Oregon "The wind machine made all of the difference." Orchard-Rite® Wind Machines • www.orchard-rite.com "You could go five years without a single insecticide. These same growers are putting on three sprays before harvest." —David Haviland